/j  /.  1 .  7  '  rJ 


Issued  Decembei  I 


U.  S.  DEPARTMENT  OF  AGRICULTURE, 

BURI  \r  OF  PLANT  INDUSTRY— Circular  No.  43. 
1'..   1    GALLON  AY,  Chief  of  Bureau. 


THE  DETERIORATION  OF  CORN 
IN  STORAGE. 


J.  W.  T.  DUVEL, 

Assistant  i\  Charge  of  Laboratory  Methods, 
I  }r  \i\  Standardization. 


SHINGIOH   :  OOVIHNUtNV    PHlNTlNG   (  ■ 


DC^M^^T" 


DEPOSITORY 


BUREAU  OF  PLANT  INDUSTRY. 


Chit/  of  Bureau,  Beverly  T.  Galloway. 
Assistant  Chief  of  Bureau,  Albert  F.Woods. 
Editor,  J.  E.  Rockwell. 
CLnf  Clerk,  James  E.  Jones. 
[Cir.  43] 

2 


B.  P.  I. -521. 

THE  DETERIORATION  OF  CORN  IX  STORAGE/ 


INTRODUCTION. 

In  February,  L909,  special  investigations  were  begun  at  Baltimore, 
M<l.,  in  cooperation  with  the  Baltimore  and  Ohio  Railroad  Company, 
for  the  purpose  of  obtaining  definite  information  regarding  the  dete- 
rioration of  shelled  corn  in  elevator  bins  and  in  grain  cars.  The  first 
series  of  experiments  in  these  investigations  comprised  tests  with  (1) 
5,550  bushels  of  corn  stored  in  a  65-foot  elevator  bin  for  69  days, 
until  the  corn  al  the  top  of  the  bin  had  become  badly  damaged; 
(2)  900  bushels  of  dried  damaged  corn  from  the  top  of  the  bin  loaded 
into  car  No.  67031  and  held  on  the  track  for  an  additional  37  days, 
and  (3)  900  bushels  of  the  best  cool  corn  from  the  same  bin  loaded 
into  car  No.  75197  and  held  on  the  track  with  the  <nv  containing  the 
dried  damaged  coin. 

In  this  preliminary  report  no  attempt  has  been  made  to  generalize 
the  results  of  the  experiments,  to  draw  any  definite  conclusion-,  or 
even  to  give  any  extended  expression  of  opinion.  The  aim  has  been 
to  outline  the  conditions  under  which  this  first  series  of  experiments 
was  made  and  to  give  a  brief  summary  of  i  he  results  obtained,  leaving 
the  individual  reader  to  formulate  his  own  theories  until  the  investi- 
gations are  more  advanced.  It  is  hoped,  however,  that  this  prelim- 
inary report  will  provoke  discussion  and  bring  about  a  better  under- 
standing of  the  purpose  and  value  of  investigations  of  this  character. 

CORN  STORED  IN  ELEVATOR  BIN. 

On  February  17  and  is.  1909,  5,550  bushels  of  shelled  corn  were 
stored  in  a  65-foot  bin  b  in  elevator  C  of  the  Baltimore  and  Ohio  Rail- 
road Company  ai  Baltimore  (Locust  Poinl  .  Md.  This  corn  was  left 
without  ''running''  until  April  27,  1909,  at  which  time  the  fermen- 
tation at  the  to])  of  the  hin  had  progressed  so  that  the  corn  was  hot 
and  sour,  the  temperature  8  inches  belov  the  surface  having  reached 
133c  K 

"  This  opportunity  is  taken  to  acknoM  ledge  tin-  cordial  cooperation  of  the  Baltimore 
and  Ohio  Railroad  Company  and  the  Baltimore  Chamber  of  Commerce,  through  its 
grain-inspection  department.  Special  thanks  are  due  to  the  various  men  assigned 
for  duly  al  the  elevator,  v.  ho  w  illingly  rendered  e\  cry  possible  assistance  while  these 
experiments  were  in  progress.     B.  T.  Gaixowai  Bureau. 

''The  hin  in  which  the  corn  was  stored  i-  near  the  center  of  the  outer  ro^  of  bins 

on  the  east  side  of  the  elevator,  il uter  6-inch  wooden  wall  of  the  hin  being  built 

against  the  heavy  brick  construction  of  the  elevator. 
[ fir.  43] 


THE   DETERIORATION    OF    CORN    IN    STORAGE. 


The  corn  used  in  these  experiments  was  taken  from  cars  selected 
from  those  received  at  Baltimore,  Md.,  on  February  16,  1900.  So 
far  as  the  records  available  show,  4,050  bushels  of  tins  corn  were 
growm  in  the  Dakotas,  the  remaining  1,500  bushels  having  originated 
in  Illinois.  The  3,050  bushels  first  run  into  the  bin  consisted  of 
practically  all  Dakota  corn.  The  next  draft  of  500  bushels  was 
Illinois  corn  with  a  small  admixture  of  Dakota  corn.  The  1,000 
bushels  following  consisted  of  Illinois  corn,  wdiile  the  1,000  bushels 
in  the  tenth  and  eleventh  drafts  at  the  top  of  the  bin  were  composed 
of  corn  from  the  Dakotas. 

In  filling  the  bin  each  draft  consisted  of  500  bushels,  with  the 
exception  of  the  first  50  bushels  at  the  bottom  of  the  bin.  After 
almost  every  draft,  samples  were  taken  with  a  4-foot  grain  trier, 
one  from  the  center  and  one  from  near  each  corner  of  the  bin,  and 
the  different  factors  representing  the  quality  and  condition  of  the 
corn  were  determined  for  each  sample.  The  average  results  of  the 
analyses  of  the  samples  representing  the  different  drafts  are  given 
in  Table  I.  These  results  show  the  moisture  content;  weight  per 
bushel;  weight  of  1,000  kernels;  sound  corn;  damaged  corn;  other 
grains;  dirt,  cobs,  etc.;  badly  broken  corn;  and  germination  of  whole 
kernels.  A  comparison  of  Table  I  with  figure  1  will  show  the  exact 
location  of  the  corn  in  the  bin  represented  by  each  set  of  averages 
given  in  the  table. 

Table  I. — Average  condition  and  quality  of  the  -5,550  bushels  of  corn  at  the  beginning 
of  the  experiment,  as  shown  by  the  analyses  of  samples  taken  with  a  4-foot  grain  trier 
after  the  different  drafts  were  emptied  into  the  bin  a 


No.  of  draft. 

Amount 
of  draft. 

Moisture 
content. 

Weight 

per 
bushel. 

Weight 
of  1.0(H) 
kernels. 

Sound 
corn . 

Dam- 
aged 
grains. 

Other 
grains. 

Weeds, 
cobs, 
dirt, 
etc. 

Badly 
broken 
corn. 

Germina- 
tion of 
whole 

kernels. 

(Bottom) 

1 

Bus. 
50 
500 
500 
500 
500 
500 
;,oii 
500 
1  000 
500 
500 

/'.  ct. 
17.8 
17.9 
17.8 
17.9 
18.0 
17.8 
18.8 
17.5 
17.0 
is  6 
18.3 

Lbs. 
53.5 
53.8 
53.6 
53.3 

52.  6 
53.6 
53.0 
54.  5 
55.0 

53.  3 
52.  X 

Grams. 
280 
294 
337 
295 
303 
296 

L'S6 

317 
330 

272 
276 

P.  ct. 
97.9 
97.6 
97.4 
96.9 

96.  2 
96  i, 
U7.7 

97.  6 
96.9 
96.3 
96.6 

P.ct. 

0.8 
1.0 

.5 
1.4 
2.5 
2.2 
1.8 
1.3 

.7 
1.4 
1.6 

P.ct. 

0.5 

.9 

1.2 
.9 
.4 
.4 
.  1 
.5 

1.  1 

.9 

P.ct. 
0.8 
.5 
.9 
.8 
.9 
.8 
.4 
.6 
2.4 
1.2 
.9 

P.ct. 
2.4 
3.1 
3.3 
2.0 
3.5 
3.3 
1.4 
3.5 
5.4 
3.9 
3.7 

P.ct. 

2 

vl.  3 

3 

4 

72.8 
73.0 

5 

77.3 

6 

7 

8  and  9 

10 

69  ii 
87.8 
95.0 

71. S 

11 

73.0 

Average 

17.8 

53.7 

301 

97.0 

1.4 

0.6 

1.0 

3.0 

80.6 

a  All  figures  in  the  table  other  than  those  in  the  first  two  columns  represent  averages,  so  thai  the  final 
average  of  all  the  com  in  the  bin  is  based  on  a  total  of  43  samples,  or  1  sample  lor  approximately  every 
130  bushels  of  corn  emptied  into  the  bin. 

As  will  be  seen  from  the  table,  the  average  moisture  content    of 

the  corn  in  the  different  drafts  varied  from  17  per  cent  in  the  eighth 

and  ninth  to  18.8  per  cent  in  the  sixth  draft,  with  an  average  of 

17.8  per  cent  for  all  of  the  corn  in  the  bin.     The  weight  per  bushel 

[Cir.  43] 


Till.    DETERIORATION    OF    CORN    [N   STORAGE.  5 

varied  from  52.6  pounds  in  the  fourth  drafl  to  55  pounds  in  the 
eighth  and  ninth,  with  ;t  total  average  of  53.7  pounds.  Similar 
variations  are  shown  in  the  other  factors,  mosl  of  which  indicate 
thai   the  corn  of  the  highest  quality  and  in  the  besl  condition  was 

the  Illinois  coin  contained  in  the  eighth  and  ninth  drafts. 

NOTES    ON     THE    TEMPERATURE     AND    THE    CONDITION    OF    THE    CORN 

w l\    THE    BIN. 

The  bin  usvA  in  this  experiment    was  previously  equipped  with 

thirteen  electrical  resistance  thermometers,  so  that  temperature 
records  of  the  coin  in  various  parts  of  the  bin  could  be  taken  at  any 
time  during  the  course  of  the  experiment.  Thermometer  No.  1  was 
ahont  :\\  feel  from  the  bottom,  near  the  center  of  the  hopper.  The 
other  thermometers  were  distributed  through  the  center  of  the  corn, 
approximately  8^  feel  apart,  excepl  that  in  the  corn  near  the  top 
of  the  bin,  where  deterioration  is  most  likely  to  begin,  additional 
thermometers  were  placed  at  various  points.  Figure  I  shows  the 
location  of  these  thermometers,  numbered  from  1  to  7  and  from  A 
to  E,  inclusive.  In  this  same  diagram  are  also  shown  the  number 
of  bushels  contained  in  each  draft,  the  average  moisture  content 
and  the  weight  per  bushel  of  the  corn  in  the  various  parts  of  the  bin 
at  the  time  of  filling,  the  temperature  of  the  corn  immediately  after 
the  bin  was  filled,  and  the  maximum  temperature  of  the  corn  at  the 
end  of  the  experiment,  which  extended  over  a  period  of  69  days. 

The  temperature  of  the  coin  immediately  after  the  bin  was  Idled 
varied  from  36  to  in  K.  As  the  bin  was  being  filled  the  atmosphere 
was  dear  and  dry.  the  relative  humidity  being  18  per  cent.  The 
temperature  of  the  air  in  the  elevator  varied  from  3G°  to  .",'.'  I  . 
"While  i  he  corn  w  as  in  storage,  temperal  tire  readings  were  made  e\  ery 
two  or  three  days  until  April  22,  when  the  corn  at  the  top  of  the  bin 
gave  evidence  <r{  very  rapid  deterioration,  necessitating  frequent 
readings  during  t be  remaining  five  da\  s  of  1  be  test . 

The  lirst  indication  that  the  corn  had  begun  to  deteriorate  was  on 
the  26th  of  March,  alter  it  had  been  in  storage  37  days,  at  which  time 
a  slight  ly  sour  odor  was  perceptible  in  the  corn  at  t  be  top  of  the  bin, 
showing  that  fermentation  had  begun.  The  highest  temperature 
recorded  at  this  time  was  12°  V..  by  thermometer  <  .  approximately 
5  feel  below  the  surface  of  the  corn.  From  this  time  on  the  increase 
in  the  temperature  of  the  500  bushels  of  corn  at  the  top  of  the  bin 
became  more  pronounced.  However.  27  days  later,  on  April  22,  the 
highesl  temperature  recorded  was  still  less  than  70  I-'.,  hut  during 
the  5  days  mi  mediately  following  a  maximum  of  L33  V.  was  reached, 
8  inches  I. clow   the  surface  of  the  grain. 

[Clr.43] 


THE   DETERIORATION    OF    CORN    IN    STORAGE. 

sW/RE CABLE 

CORNER '2 


/& 3%  MO/STURE.  52.8 L6s.  per  Bu. 
TEMPERATURE    38°  to  /33°F 

/8.6%  MO/STURE.   53.3  Lbs.  per  Bu. 
TEMPERATURE    38°to //5°E 


/70%  MO/STURE.  55.0  Lb  s.  per  Bu. 
TEMPERATURE  38°  to  56.5° E 


17. 5°/o  MOISTURE.  54.5 Lbs.  per  Bu. 
TEMPERATURE  40°  to  40. 5° E 

/8. 8  %  MOISTURE.  53. 0 Lbs. per  Bu. 
TEMPERATURE   36.5° to  41. 5°E 

17.8  %M0ISTURE.  53 6 Lbs.  per  Bu. 
TEMPERATURE     36  °  to  40. 5°E 


Y8. 0  %  MO/STURE.  52.  6 Lbs.  perBu. 
TEMPERATURE    36°  to  39. 5° E 


179  °/o MO/STURE.  53.3 Lbs  per  Bu. 
TEMPERATURE    36°  to  40.5 °E 

/7 8% MO/STURE.  53.6Lbsper Bu. 
TEMPERATURE  38°  to  4-/.5°E 

/7.9  %  MO/STURE.  53. 8  Lbs  per  Bu. 
TEMPERATURE    36°  to  4/.5°E 


/78°/o MO/STURE.  53.5 Lbs. per  Bu. 
TEMPERATURE   36°  to  4-/.5°E 


Fig.  1. — Diagram  showing  the  position  of  the  thermometers;  the  number  of  bushels,  the  moisture  con  tent, 
and  the  weight  per  bushel  for  each  draft;  and  the  temperature  of  the  corn  at  the  beginning  and  at  the 
end  of  the  experiment. 
rCir.  43] 


CHE    PI.  I  ERIOB  \  i  [ON    0]     CORN    IN   STORAGE.  7 

On  March  •'!!  three  holes  were  bored  through  the  wall  of  the  bin  on 
the  side   nearest    the   interior  of  the  house.     One  hole  was   bored 

approximate^    10  feel    from  the  bottom,  another  25  Feel   fr the 

bottom,  and  the  third  10  feet  from  the  bottom  of  the  bin,  or  20  feel 
from  the  top  of  tin*  grain.  Samples  taken  through  these  holes  with 
a  4-foot  grain  trier  showed  thai  the  corn  had  not  changed  materially 
since  it  was  first  placed  in  the  bin,  no  unnatural  odors  being  percep- 
tible. On  the  --a  i ue  date  samples  taken  with  a  long  grain  t  rier  from 
7  feet  below  the  surface  showed  the  corn  at  that  point  to  be  slightly 
musty. 

Samples  taken  on  April  3  from  3,  7.  and  12  feet  below  the  surface 
showed  mure  pronounced  odors  in  the  corn  at  3  and  7  feet,  but  no 
odor  could  be  detected  in  t  he  samples  t  aken  at  12  feet .  At  t  bis  t  ime 
the  maximum  temperature  of  the  corn  l_'  feel  below  the  surface  was 
42  !•'.  The  highest  temperature  in  the  upper  500  bushels  was  l.V.  ~ 
F.  On  April  6  the  corn  near  the  top  of  the  bin  was  \ er\  musty, 
although  the  maximum  temperature  was  onlj  is  !•'.  On  April  13, 
samples  were  again  taken  from  12  feet  below  the  surface  but  revealed 
qo  odors  indicating  deterioration. 

On  April  19  the  maximum  temperature  in  the  500  bushels  of  corn 
at  the  top  of  the  bin  was  (ill  V.,  as  registered  by  thermometer  A.  8 
inches  below  the  surface.  The  corn  near  the  top  at  this  time  was 
very  musty  and  a  considerable  quantity  of  fresh  mold  was  growing  on 
the  kernels.  The  temperature  of  the  corn  12  feet  below  the  surface. 
as  registered  l>\  thermometer  .1,  was  56°  F.,  which  was  within  one- 
half  degree  of  the  highest  temperature  recorded  at  that  depth  during 
the  cut  ire  test . 

On  April  26,  samples  were  again  taken  through  the  holes  in  the 
side  of  the  bin  at  1 I),  '_'.">,  and  10  feet  from  t  he  holt  mn,  together  with  a 
number  of  samples  represent  ing  t  he  1 ,000  bushels  at  t  he  top  of  the  bin. 
At  this  time  the  com  at  the  top  of  the  bin  was  hot,  musty,  and  sour, 
but  no  odor  could  be  detected  on  the  samples  taken  through  the  hole 
in  feel  from  the  bottom  of  the  bin.  However,  the  samples  taken 
through  the  holes  25  and  10  feel  from  the  bottom  of  the  bin  showed 
that  the  corn  near  the  bin  walls  at  those  points  was  slightly  sour. 
This  condition  was  shown  more  clearly  when  the  bin  was  emptied 
the  Following  day.  the  corn  having  a  tendency  to  adhere  to  the  sides. 
In  emptying  the  bin  the  corn  from  the  sides  became  unevenly  mixed 
with  the  better  corn  from  the  interior,  so  that  an  odor  was  percep- 
tible on  a  considerable  portion  of  the  entire  hulk. 

The  fermentation  in  the  upper  500  bushels  of  com  was  \er\   active 

at  this  i  me  and  the  temperature  was  increasing  rapidly.     On  April 

25  thermometer  No.  7.  in  the  center  about  5  feel  beneath  the  surface 

of  the  com,  registered  s7"  V.     At  8  o'clock  the  following  morning 

[t'e 


8 


THE   DETERIORATION    OF    CORN    IN    STORAGE. 


this  same  thermometer  registered  102°;  at  11.45  a.  m.,  105°;  at  3.10 
p.  m.,  107°.  and  at  9  o'clock  the  morning  of  the  27th,  115°,  an  increase 
of  28  degrees  F.  in  48  hours.  The  highest  temperature  registered  on 
April  27  was  133°  F.,  in  corner  No.  4,  8  inches  below  the  surface  of 
the  corn.  In  corner  No.  1,  14  inches  below  the  surface,  the  tem- 
perature was  110°;  in  corner  No.  2,  112°;  in  corner  No.  3,  125°:  and 
in  corner  No.  4,  132+°.  Thermometer  B,  in  corner  No.  2,  the  same 
depth  below  the  surface  as  thermometer  No.  7,  registered  71.5°  F. 


1909.  FEBRUARY 


MARCH. 


APRIL. 


1909. 


Ill     ■!■■    I 


WEATHER  RECORD. 


IB 


-fi^/N  OR  SNOW,    .01  fNCH  OR  MORE.  \  \  =  RAIN  OR  SNOW,     TRACE. 

I  1=  NO  RAIN    OR   SNOW. 


Fig.  2. — Diagram  showing  the  temperature  of  the  corn  in  various  parts  of  the  bin.  the  daily  maximum  and 
minimum  air  temperature,  and  the  precipitation  from  February  17  to  April  27,  1909. 

A  clearer  understanding  of  these  conditions  will  be  had  by  consult- 
ing figure  2,  which  shows  the  temperature  of  the  corn  in  various  parts 
of  the  bin,  together  with  the  daily  maximum  and  minimum  air  tem- 
perature, and  the  general  character  of  the  precipitation  during  the 
GO  days  covered  by  the  experiment. 


CONDITION    OF    THE    CORN    AT   THE    END    OF    THE    EXPERIMENT. 

As  shown  in  figure  2,  the  only  marked  increase  in  temperature  was 
in  the  G  or  7  feet  of  corn  at  the  top  of  the  bin.  The  maximum  tem- 
perature registered  by  thermometers  No.  6  and  A,  approximately  12 

[Cir.43] 


Ill  I .    DETERIORATION    OF   CORN    IN    STORAGE.  \) 

feel  below  the  surface,  was  51  and  ">f>\  !•'..  respectively.  The  tem- 
perature of  the  corn  in  the  lower  pari  of  the  bin  varied  from  39-J°  to 
4H°  V.,  as  compared  with  a  variation  of  from  36°  to  40°  F.  at  the 
beginning  of  the  experiment. 

The  moisture  content  of  the  corn  immediately  at  the  surface  was 
14.95  per  cent,  <>r  .'>..!">  per  cent  less  than  on  February  17.  The 
moisture  content  of  the  1,000  bushels  at  the  top  of  the  bin,  exclusive 
of  the  corn  on  the  surface,  was  slightly  higher  than  when  the  corn  was 
placed  in  the  bin,  showing  that  the  deterioration  of  the  corn  was 
resulting  in  the  formation  of  more  water  than  was  being  given  off  by 
evaporat  ion.  The  weight  per  bushel  of  the  surface  corn  was  5  I  pounds, 
while  the  weighl  of  the  remainder  of  the  upper  1,000  bushels  had 
decreased  from  53  to  51  pounds. 

The  germination  of  the  poorest  corn  from  the  top  of  the  bin  varied 
from  0  to  17  per  cent,  with  an  average  of  10.3  per  cent,  as  compared 
with  an  average  of  7_\ 4  per  cent  on  February  17.  This  corn  was 
damaged  so  that  many  of  the  germs  were  badly  discolored.  The 
average  germination  of  the  1,070  bushels  taken  from  the  top  of  the 
bin  for  further  experiment,  which  included  not  only  the  hot  corn 
hut  all  that  had  a  temperature  over  50°  F.,  was  42.6  per  cent  after 
being  handled,  dried,  and  loaded  into  car  No.  ti7():J>1. 

The  corn  in  the  lower  1")  feet  of  the  bin,  except  !»()()  bushels  of  the 
best  quality  which  was  loaded  into  car  No.  7.">1!)7  for  further  test, 
after  being  handled  over  three  elevators  and  dried  to  1  L87  per  cent 
of  moisture,  was  given  a  grade  <>f  "Mixed  corn."  The  germination 
of  this  corn  was  SO.S  per  cent  at  the  beginning  of  the  experiment,  71.4 
per  cent  when  drawn  from  the  bin,  and  81.4  per  cent  after  being 
handled  and  dried. 

The  total  loss  in  weight,  as  shown  by  the  certificates  furnished  by 
the  weighman  of  t  he  ( Jhamber  of  Commerce,  resulting  from  filling  and 
emptying  the  bin  and  the  evaporation  during  the  (>'.»  days  in  storage, 
amounted  to  310  pounds,  or  slightly  less  than  one-tenth  of  l  per  cent. 

DRIED    DAMAGED  CORN   FROM  TOP   OF   BIN    STORED  IN  CAR. 

The  1.1)7(1  bushels  of  corn  drawn  from  the  top  of  the  bin  was 
weighed,  handled  over  three  elevators,  and  reweighed,  after  which 
it  was  artificially  dried  in  a  grain  drier  at  a  temperature  varying  from 
151    to  163     I-'.     The  average  moisture  content  of  this  corn  as  taken 

from  the  bin  was  18.64  per  cent.  The  average  moisture  content 
when  emptied  into  the  drier  was  18.30  per  cent,  of  ;,  reduction  of 
i).:;  i  of  1  per  cent  a-  a  result  of  the  handling,  which  i^  equivalent  to 
a  loss  in  weight  of  u.  i  ,,|'  i   per  .-cut.       In  drying,  the  moisture  con- 


Bureau  "i'  I'l.mi  Industry .  U.  S.  Dept.  of  Agriculture,  entitled  "Mois- 
ture  Contenl  and  Shrinkage  in  Grain,"  explains  why  this  dil  cists  and  how  it 

is  calculated. 

[CIr.  i:i] 


10  THE    DETERIORATION    OF    CORN    IN    STORAGE. 

tent  was  reduced  from  18.3  per  cent  to  14.57  per  cent,  a  reduction  of 
3.73  per  cent,  which  is  equivalent  to  a  loss  in  weight  of  4.44  percent. 

After  this  corn  was  dried  and  thoroughly  cooled,  900  bushels,  having 
an  average  moisture  content  of  14.57  per  cent,  were  loaded  into  car 
No.  67031  as  if  intended  for  shipment.  The  car  was  run  out  into  the 
yard  and  left  standing  on  the  track  fully  exposed  to  all  atmospheric 
changes.  The  temperature  of  this  corn  immediately  after  it  was 
loaded  into  the  car,  after  drying  and  cooling,  on  April  27,  varied  from 
57°  to  58°  F.  Frequent  temperature  readings  were  made  up  to  and 
including  May  25,  when  the  highest  temperature  at  any  point  in  the 
corn  was  66°  F.,  an  increase  of  only  8  or  9  degrees,  although  the 
temperature  of  the  air  in  the  car  had  varied  from  56°  to  82°  F. 
and  the  temperature  of  the  air  outside  of  the  car  from  41  °  to  90°  F. 
On  May  25,  after  being  in  the  car  28  days  without  any  noticeable 
change  in  condition,  the  corn  was  unloaded,  elevated,  and  weighed, 
and  then  returned  to  the  car  and  left  an  additional  9  days  on  the 
track.  The  air  temperature  at  this  time  was  73  °  F. ,  resulting  in  a  very 
slight  increase  in  the  temperature  of  the  corn  by  the  time  it  was 
returned  to  the  car. 

On  June  3  the  temperature  of  the  corn  was  67°  F.,  an  increase  of 
only  10  degrees  during  the  entire  37  days  that  this  corn  was  in  the 
car.  The  condition  of  the  corn  was  fully  as  good  if  not  better  than 
when  it  was  placed  in  the  car  on  April  27,  although  the  odor  resulting 
from  the  fermentation  of  the  corn  while  in  the  bin  had  not  entirely 
disappeared. 

On  June  3  the  moisture  content  of  the  corn  on  the  surface  was  13.1 
per  cent,  with  14.48  per  cent  for  the  remainder  of  the  corn  in  the  car, 
a  difference  of  1.38  per  cent  in  the  moisture  content,  which  is  equiva- 
lent to  a  shrinkage  in  weight  in  the  surface  corn  of  1.59  per  cent  in  9 
days  from  May  25  to  June  3. 

UNDBIED  CORN  FROM  BIN  STORED  IN  CAR. 

In  order  to  secure  data  for  comparison,  900  bushels  of  the  best  cool 
corn  from  the  bin,  principally  the  Illinois  corn  from  the  eighth  and 
ninth  drafts,  were  loaded  into  car  No.  75197  and  placed  on  the  track 
alongside  of  the  car  containing  the  900  bushels  of  dried  damaged  corn 
from  the  top  of  the  bin.  The  temperature  of  this  coin  while  still  in 
the  bin  varied  from  40°  to  42°  F.,  but  in  "running"  from  the  bin, 
elevating  to  the  scale,  and  loading  into  the  car,  the  temperature 
was  increased  so  that  the  temperature  of  the  corn  after  being  loaded 
was  48°  F.  The  air  temperature  at  this  time  was  51  °  F.  and  the  rela- 
tive humidity  of  the  atmosphere  70  per  cent.  The  average  moisture 
content  of  this  car  of  coin  was  17.5  per  cent,  and  the  weight  per 
bushel  was  55.3  pounds. 

|  CIr.  131 


I  II I     |i|   II  RIOB  \  I  [OK    OF    CI  >i:X    IN    STOB  \.GI . 


11 


On  M;i\  20,  after  standing  on  the  track  23  daj  s,  the  corn  in  this  car 
began  to  show  unmistakable  signs  of  deterioration.  At  that  time  the 
maximum  temperature  of  the  corn  was  75  !•'..  and  it  had  a  distinctly 
Mini-  an. I  musty  odor.  Five  days  later  the  maximum  temperature 
was  L22  I'-.  in  the  brake  end  of  the  car,  approximately  6  inches  below 
the  -hi  face  of  the  corn.  Tin'  a\  erage  weight  per  bushel  had  decreased 
from  •">■">.•'!  pounds  to  52.6  pounds.  The  moisture  content  varied  from 
13.6  per  cent  in  the  corn  at  the  surface  to  17..")  per  cent  where  the 
tempera!  lire  was  1 '_''_'  F.,  as  compared  with  a  varial  ion  of  from  17  per 
cent  tu  17. 7  per  cent  at   the  time  the  corn  was  loaded   into  the  car. 


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Diagram  showing  the  temperature  of  the  undried  corn  in  car  No.  75197  and  of  ilio  dried  damaged 

corn  in  car  No.  G7031;    the  daily  maximum  air  temperature;  and  the  weather  recor  I  from  April  27  to 
June  :s.  1909,  whlli  "  elevator  yards. 

( )n  Mas  _'"i  1  hi-  corn  was  unloaded,  weighed,  handled  over  five  eleva- 
tor-, reweighed,  screened,  weighed  a  third  time,  and  returned  t<>  the 
car  for  further  obsen  ation.  When  the  emu  was  returned  to  the  car 
the  second  time  (May  25  •  the  temperature  was  7'l  1''..  approximately 
the  same  a-  the  temperature  of  the  air  at  the  time  the  corn  was 
handled.  On  .lime  :;.  9  days  later,  the  corn  in  thi-  car  was  again  hot. 
the  maximum  temperature  being  L12  1''..  showing  that  hoi  corn  i- 
iiut  made  safe  for  shipment  when  cooled  -imply  by  handling. 

Figure  •">  shows  the  changes  in   temperature  in  both  the  car  of 
undried  corn  and  the  car  of  dried  damaged  corn  while  on  the  track 

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12  THE    DETERIORATION    OF    CORN    IN    STORAGE. 

from  April  27  to  May  25  and  from  May  25  to  June  3,  together  with  the 
daily  maximum  air  temperature  and  the  weather  record  for  the  same 
period.  The  diagram  also  shows  that  only  the  corn  near  the  surface 
was  influenced  by  the  temperature  of  the  outside  air. 

LOSS    EN    MOISTURE    AND    SHRINKAGE. 

When  the  undried  corn  from  the  bin  was  first  loaded  into  car  No. 
75197,  on  April  27,  the  average  moisture  content  was  17.47  per  cent. 
On  May  25,  when  the  maximum  temperature  of  the  corn  was  122°  F., 
the  average  moisture  content  of  the  surface  corn  was  13.55  per  cent. 
Samples  taken  from  5  inches  below  the  surface  showed  a  moisture 
content  of  17  per  cent.  The  highest  moisture  content  found  was 
17.5  percent,  in  samples  taken  at  the  point  where  the  temperature 
was  122°  F. 

The  shrinkage  in  weight  in  the  layer  of  corn  at  the  surface,  based  on 
the  reduction  in  moisture  of  3.92  per  cent,  was  4.53  per  cent.  On 
May  25  this  corn  was  unloaded  and  reweighed  by  the  weighman  of 
the  Chamber  of  Commerce  on  the  scales  regularly  used  at  the  ele- 
vator. The  loss  in  weight  in  the  loading  and  unloading  and  through 
evaporation  while  in  the  car  from  April  27  to  May  25  was  367  pounds, 
or  0.728  of  1  per  cent.  This  corn  was  then  handled  over  five  elevators, 
screened,  weighed,  and  reloaded.  In  this  handling  and  reloading 
the  moisture  content  was  reduced  to  16.55  per  cent,  or  0.92  of  1  per 
cent  less  than  when  the  corn  was  first  loaded  into  the  car  on  April 
27,  which  is  equivalent  to  a  loss  in  weight  of  1.1  per  cent  due  to  the 
evaporation  of  moisture  while  in  the  car  and  in  the  handling  of  the 
hot  corn  in  the  elevator.  On  June  3,  this  car  of  corn,  cooled  by 
handling,  was  again  hot,  the  temperature  having  increased  from  73°  F. 
to  112°  F.  from  May  25  to  June  3.  The  average  moisture  content  of 
the  surface  corn  was  only  13.95  per  cent,  as  compared  with  16.55  per 
cent  when  reloaded,  a  reduction  in  moisture  of  2.6  percent  in  9  days. 

The  low  moisture  content  of  the  surface  corn  showed  that  water 
was  being  lost  by  evaporation  and  that  this  evaporation  is  quite 
rapid  when  the  temperature  of  the  corn  is  relatively  high.  It  must 
be  remembered,  however,  that  this  car  was  opened  frequently  and 
the  com  on  the  surface  more  or  less  disturbed  in  the  securing  of  sam- 
ples, in  reading  temperatures,  etc.,  so  that  the  same  results  might 
not  apply  in  the  same  degree  to  corn  in  transit  where  the  cars  are 
unopened  from  point  of  shipment  to  destination. 

Approved: 

James  Wilson, 

Secretary  of  Agriculture. 

Washington,  I).  C,  November  5,  1009. 

|  Cir.  43] 

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